Could i be pregnant ?

i got my period on the 15th of march like always im like clockwork then i got it again on the 21st for 3 days both were normal bleeding.its the 17th of april no period ive been cramping on and of one one side or the other into my legs and lower back i was nasous for 2 days and my have been heavier and sore sometimes they get stinging sensations theyve been sore for 3 weeks i tooka pregnancy test today april 17th and it was negative i was wondering if i should test again and if its a possibility that i could be prego i donthave a doc to go to right now in case thats your answear just want your insight thank you